U.S. patent number 6,350,384 [Application Number 09/637,924] was granted by the patent office on 2002-02-26 for silicon containing multi-arm star polymers.
This patent grant is currently assigned to Dow Corning Corporation. Invention is credited to Agnes M. de Leuze-Jallouli, Petar Radivoj Dvornic, Jin Hu, Michael James Owen, Paul Lane Parham, Susan Victoria Perz, Scott Daniel Reeves.
United States Patent |
6,350,384 |
Dvornic , et al. |
February 26, 2002 |
Silicon containing multi-arm star polymers
Abstract
Multi-arm star polymers are derived from silicon containing
dendrimers and have arms containing the moiety ##STR1## where each
R' can be the same or different and is an alkyl group containing
1-6 carbon atoms such as methyl and ethyl or an aryl group such as
phenyl; R" is alkylene radical --(CH.sub.2).sub.a -- in which a has
a value of 2 or 3; and R'" is the --(CH.sub.2).sub.b CH.sub.3 group
in which b has a value of 1-50. These compositions can be used for
dissolving metals and other electrophiles.
Inventors: |
Dvornic; Petar Radivoj
(Midland, MI), Hu; Jin (Midland, MI), de Leuze-Jallouli;
Agnes M. (Largo, FL), Owen; Michael James (Midland,
MI), Parham; Paul Lane (Midland, MI), Perz; Susan
Victoria (Essexville, MI), Reeves; Scott Daniel
(Framingham, MA) |
Assignee: |
Dow Corning Corporation
(Midland, MI)
|
Family
ID: |
24557914 |
Appl.
No.: |
09/637,924 |
Filed: |
August 14, 2000 |
Current U.S.
Class: |
210/688; 210/912;
524/431; 524/432; 525/474; 525/936; 525/431; 524/430 |
Current CPC
Class: |
C08G
81/00 (20130101); C08G 83/003 (20130101); Y10S
525/936 (20130101); Y10S 210/912 (20130101) |
Current International
Class: |
C08G
81/00 (20060101); C08G 83/00 (20060101); C02F
001/62 () |
Field of
Search: |
;525/431,936,474,430,432
;210/688,912 |
References Cited
[Referenced By]
U.S. Patent Documents
|
|
|
5387617 |
February 1995 |
Hedstrand et al. |
5560929 |
October 1996 |
Hedstrand et al. |
5739218 |
April 1998 |
Dvornic et al. |
5902863 |
May 1999 |
Dvornic et al. |
5938934 |
August 1999 |
Balogh et al. |
|
Primary Examiner: Moore; Margaret G.
Assistant Examiner: Zimmer; Marc S.
Attorney, Agent or Firm: DeCesare; James L.
Claims
What is claimed is:
1. A composition of matter comprising a multi-arm star polymer
derived from a silicon containing dendrimer, the star polymer
having a plurality of arms containing the moiety ##STR9##
where each R' is an alkyl group containing 1-6 carbon atoms or an
aryl group; R" is alkylene radical --(CH.sub.2).sub.a -- in which a
has a value of 2 or 3; and R'" is the --(CH.sub.2).sub.b CH.sub.3
group in which b has a value of 1-50.
2. A composition according to claim 1 in which the silicon
containing dendrimer is a poly(amidoamine-organosilicon) (PAMAMOS)
or poly(propyleneimine-organosilicon) (PPIOS) dendrimer.
3. A composition of matter comprising an electrophile encapsulated
within a multi-arm star polymer selected from the group consisting
of (i) a non-crosslinked multi-arm star polymer derived from amine
or imine terminated dendrimers which have been reacted with a
monofunctional glycidoxy organosilicon composition, and (ii) a
non-crosslinked multi-arm star polymer derived from silicon
containing dendrimers, the multi-arm star polymer (ii) having a
plurality of arms containing the moiety ##STR10##
where each R' is an alkyl group containing 1-6 carbon atoms or an
aryl group; R" is alkylene radical --(CH.sub.2).sub.a -- in which a
has a value of 2 or 3; and R'" is the --(CH.sub.2).sub.b CH.sub.3
group in which b has a value of 1-50.
4. A composition according to claim 3 in which the dendrimers are
selected from the group consisting of polyamidoamine (PAMAM),
polypropyleneimine (PPI), poly(amidoamine-organosilicon) (PAMAMOS),
and poly(propyleneimine-organosilicon) (PPIOS) dendrimers.
5. A composition according to claim 3 in which the electrophile is
(i) a metal cation, (ii) a metal salt, (iii) a metal oxide, (iv) an
elemental metal, (v) a water soluble organic molecule, or (vi) a
water soluble organometallic molecule.
6. A composition according to claim 5 in which the electrophile is
a metal cation selected from the group consisting of Cu.sup.1+,
Cu.sup.2+, Fe.sup.2+, Fe.sup.3+, Au.sup.3+, Ag.sup.+, Rh.sup.3+,
Ni.sup.2+, and Cd.sup.2+.
7. A composition according to claim 5 in which the electrophile is
elemental metal Au.sup.0, Ag.sup.0, Co.sup.0, Cu.sup.0, Ni.sup.0,
or Pt.sup.0.
8. A composition according to claim 5 in which the electrophile is
a water soluble organic molecule or a water soluble organometallic
molecule selected from the group consisting of pigments, dyes,
indicators, light sensitizers, radiation sensitizers, catalysts,
electro-conductive materials, magnetic materials, non-linear
optical materials, liquid crystalline materials, light emitting
materials, fluorescent materials, phosphorescent materials,
polymerizable monomers, polymerization initiating materials,
biomedical materials, pharmaceutical products, biologically active
materials, biologically inactive materials, antiseptic materials,
and surface active agents.
9. A method of transferring an electrophile from an aqueous phase
to an organic phase comprising adding an aqueous solution of an
electrophile to an organic solution containing a multi-arm star
polymer, and mixing the aqueous solution and the organic solution,
the multi-arm star polymer being selected from the group consisting
of (i) multi-arm star polymers derived from amine or imine
terminated dendrimers which have been reacted with a monofunctional
glycidoxy organosilicon composition, and (ii) multi-arm star
polymers derived from silicon containing dendrimers, the multi-arm
star polymers (ii) having a plurality of arms containing the moiety
##STR11##
where each R' is an alkyl group containing 1-6 carbon atoms or an
aryl group; R" is alkylene radical --(CH.sub.2).sub.a -- in which a
has a value of 2 or 3; and R'" is the --(CH.sub.2).sub.b CH.sub.3
group in which b has a value of 1-50.
10. A method according to claim 9 in which the dendrimers are
selected from the group consisting of polyamidoamine (PAMAM),
polypropyleneimine (PPI), poly(amidoamine-organosilicon) (PAMAMOS),
and poly(propyleneimine-organosilicon) (PPIOS) dendrimers.
11. A method according to claim 9 in which the electrophile is (i)
a metal cation, (ii) a metal salt, (iii) a metal oxide, (iv) an
elemental metal, (v) a water soluble organic molecule, or (vi) a
water soluble organometallic molecule.
12. A method according to claim 11 in which the electrophile is a
metal cation selected from the group consisting of Cu.sup.1+,
Cu.sup.2+, Fe.sup.2+, Fe.sup.3+, Au.sup.3+, Ag.sup.+, Rh.sup.3+,
Ni.sup.2+, and Cd.sup.2+.
13. A method according to claim 11 in which the electrophile is
elemental metal Au.sup.0, Ag.sup.0, Co.sup.0, Cu.sup.0, Ni.sup.0,
or Pt.sup.0.
14. A method according to claim 11 in which the electrophile is a
water soluble organic molecule or a water soluble organometallic
molecule selected from the group consisting of pigments, dyes,
indicators, light sensitizers, radiation sensitizers, catalysts,
electro-conductive materials, magnetic materials, non-linear
optical materials, liquid crystalline materials, light emitting
materials, fluorescent materials, phosphorescent materials,
polymerizable monomers, polymerization initiating materials,
biomedical materials, pharmaceutical products, biologically active
materials, biologically inactive materials, antiseptic materials,
and surface active agents.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
REFERENCE TO A MICROFICHE APPENDIX
Not applicable.
FIELD OF THE INVENTION
This invention is directed to certain compositions of matter
including multi-arm star polymers derived from silicon containing
dendrimers in which the arms of the resulting star polymer contain
in their molecule the characteristic moiety ##STR2##
where each R' can be the same or different and is an alkyl group
containing 1-6 carbon atoms such as methyl and ethyl or an aryl
group such as phenyl; R" is alkylene radical --(CH.sub.2).sub.a --
in which a has a value of 2 or 3; and R'" is the --(CH.sub.2).sub.b
CH.sub.3 group in which b has a value of 1-50. The invention is
also directed to the use of such compositions of matter, and the
use of multi-arm star polymers derived from amine or imine
terminated dendrimers which have been epoxidized with
monofunctional glycidoxy organosilicon compositions, for dissolving
metals and other electrophiles.
BACKGROUND OF THE INVENTION
While U.S. Pat. No. 5,902,863 (May 11, 1999) and U.S. Pat. No.
5,938,934 (Aug. 17, 1999) describe networks containing dendrimers
having in their molecule groups at the outer surface containing the
moiety ##STR3##
these prior art patents do not describe any dendrimers containing
the moiety ##STR4##
where R', R", and R'" have the same meaning as defined above.
This is a significant distinction since the prior art compositions
containing an --SH moiety are inherently very reactive, possess an
odor of rotten eggs, and are very unstable when exposed to open
environment. In contrast, compositions of this invention containing
the --SR'" moiety are inherently non-reactive, possess no odor, and
are very stable when exposed to open environment. In addition,
prior art compositions containing the --SH moiety have very limited
use, i.e., for preparing networks or other dendrimers; whereas
compositions of the invention containing the --SR'" moiety have a
variety of uses as discussed hereafter.
While U.S. Pat. No. 5,739,218 (Apr. 14, 1999) describes certain
dendrimer compositions obtained by epoxidation of amine or imine
terminated dendrimers, it does not suggest use of the resulting
dendrimers for dissolving metals and other electrophiles. Such a
use cannot be inferred from a consideration of U.S. Pat. No.
5,938,934, since the '934 patent relates specifically to the use of
networks prepared from such dendrimers, rather than to the use of
the dendrimer composition itself which is not a network. This is a
significant distinction when one considers that networks of
dendrimers, i.e., crosslinked molecules, are generally insoluble in
all solvents, whereas the non-crosslinked dendrimers themselves are
generally soluble in many solvents.
Lastly, dendrimers and star polymers according to this invention
should not be confused with dendrimers and star polymers described
in U.S. Pat. No. 5,387,617 (Feb. 7, 1995) and U.S. Pat. No.
5,560,929 (Oct. 1, 1996), since the hydrophobic tail used to cap
dendrimers and star polymers in the '617 and '929 patents does not
contain silicon atoms. Rather, the capping materials used in the
'617 and '929 patents are hydrocarbon chlorides and bromides such
as cetyl bromide or .alpha.,.beta.-epoxides derived from
epoxidation of terminal olefins such as 1,2-epoxydecane.
BRIEF SUMMARY OF THE INVENTION
This invention is directed to multi-arm star polymers containing a
hydrophilic dendritic core and hydrophobic silicon containing arms.
The number of arms per molecule is dependent upon the functionality
of the dendrimer precursor used in its synthesis, and the degree of
conversion achieved during the synthesis. Depending upon the
density of functionality, i.e., the generation of the dendrimer
precursor used in the synthesis, the number of arms may range from
3 to several thousand, but generally the number of arms will range
between 3-4,000, preferably 4-300.
Dendrimer precursors suitable for use in the manufacture of these
multi-arm star polymers may consist of a polyamidoamine (PAMAM),
polypropyleneimine (PPI), poly(amidoamine-organosilicon) (PAMAMOS),
or poly(propyleneimine-organosilicon) (PPIOS), dendrimer. Each of
the arms of the multi-arm star polymers contain silicon, and the
number of silicon atoms in each of the arms of the star polymer can
vary from a single silicon atom to as many as about 30 silicon
atoms.
In general, these multi-arm star polymers can be prepared by two
different synthetic processes. A first method involves a thiol
addition to the unsaturated groups of a dendrimer containing
silicon atoms, in the presence of a catalyst such as
2,2'-azobisisobutyronitrile (AIBN); while a second method involves
epoxidation of an amine or imine terminated dendrimer using a
monofunctional glycidoxypolysiloxane, i.e., a monoepoxypropoxy
functional polysiloxane.
It has been found that these multi-arm star polymers evidence
properties enabling their use in several different and unusual
applications, including their use as (i) surface active phase
transfer agents, (ii) solubilizers for inorganic cations, metal
atoms, and nanoscopic clusters in hostile organic environments,
(iii) macromolecular hosts for complexing and encapsulating
electrophiles, (iv) catalysis, (v) molecular sensors, (vi)
harvesting of metals from aqueous salt solutions, (vi) harvesting
of residual polymerization catalysts or initiators from
organosilicon polymers, and (vii) compatibilization of
organosilicon polymers and rubbers with various inorganic, organic,
or organometallic electrophiles.
In particular, their use as phase transfer agents (i) and
solubilizers (ii) was demonstrated by a transport of copper
Cu.sup.2+ cations from an aqueous medium into an organic medium,
and their dissolution and retention in the dissolved state; as well
as the formation, dissolution, and retention of copper Cu.sup.0
metal, in an organic solvent, which represents hostile environments
for such species.
As used herein, the term electrophile is intended to mean and
includes (i) metal cations, (ii) metal salts, (iii) metal oxides,
(iv) elemental metals, (v) water soluble organic molecules, and
(vi) water soluble organometallic molecules. Some representative
metal cations are Cu.sup.1+, Cu.sup.2+, Fe.sup.2+, Fe.sup.3+,
Au.sup.3+, Ag.sup.+, Pt.sup.3+, Rh.sup.3+, Ni.sup.2+, Co.sup.2+,
and Cd.sup.2+. Some representative elemental metals are Au.sup.0,
Ag.sup.0, Co.sup.0, Cu.sup.0, Ni.sup.0, or Pt.sup.0. Some
representative water soluble organic molecules and water soluble
organometallic molecules are pigments, dyes, indicators, light
sensitizers, radiation sensitizers, catalysts, electro-conductive
materials, magnetic materials, non-linear optical materials, liquid
crystalline materials, light emitting materials, fluorescent
materials, phosphorescent materials, polymerizable monomers,
polymerization initiating materials, biomedical materials,
pharmaceutical products, biologically active materials,
biologically inactive materials, antiseptic materials, and surface
active agents. Some particular representative water soluble organic
molecules are C.sub.37 H.sub.27 N.sub.3
O.sub.3.multidot.2NaSO.sub.3 (methylene blue) and C.sub.15 H.sub.15
N.sub.3 O.sub.2 (methyl red).
These and other features of the invention will become apparent from
a consideration of the detailed description.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
Not applicable.
DETAILED DESCRIPTION OF THE INVENTION
In the compositions according to this invention, the multi-arm star
polymer is derived from a dendrimer core, and the arms of the
multi-arm star polymer is formed exclusively of organosilicon
moieties or polyalkene moieties such as polymethylene. In
particular, among the dendrimer cores found to be most suitable for
forming these multi-arm star polymers, are for example,
polyamidoamine (PAMAM) dendrimer cores, polypropyleneimine (PPI)
dendrimer cores, poly(amidoamine-organosilicon) (PAMAMOS) dendrimer
cores, and poly(propyleneimine-organosilicon) (PPIOS) dendrimer
cores. These dendrimer cores are made up of (a) water soluble
amidoamine repeat units such as --[(CH.sub.2).sub.2
--CO--NH--(CH.sub.2).sub.2 --N].dbd., b) water soluble
propyleneimine units such as --[(CH.sub.2).sub.3 N].dbd., and (c)
organosilicon units.
Such compositions can be prepared by at least two different
synthetic methods. The first method is a thiol addition to an
unsaturated vinylsilyl functionalized PAMAMOS dendrimer or to an
allylsilyl functionalized PAMAMOS dendrimer, whereas the second
method involves the epoxidation of an amine or imine terminated
PAMAM or PPI dendrimer using a monoepoxypropoxy functional
polysiloxane.
In particular, the thiol addition reaction route to PAMAMOS or
PPIOS multi-arm star polymers according to the invention involves a
catalyzed reaction of a thiol and an unsaturated vinylsilyl
terminated PAMAMOS or PPIOS dendrimer or an allylsilyl terminated
PAMAMOS or PPIOS dendrimer, as illustrated below for the vinyl
terminated reagent: ##STR5##
The catalyst used in the THIOL ADDITION REACTION can be a free
radical initiator such as 2,2'-azobisisobutyronitrile (AIBN). The
amount of free radical initiator required is typically between
about 0.5-2 weight percent with respect to the amount of the
PAMAMOS DENDRIMER. Free radical initiators other than AIBN can be
used, for example, other azo compounds such as
4,4'-azo-4-cyanopentanoic acid (ACPA), peroxides such as hydrogen
peroxide and alkyl peroxides, persulfates, peresters, and
peracids.
Common solvents can be employed such as methanol, isopropanol,
N,N-dimethylformamide, tetrahydrofuran (THF), dimethylacetamide,
dimethylsulfoxide, N-methyl-2-pyrrolidone, hexamethylphosphoramide,
chloroform, methylene chloride, tetramethylurea, and mixtures
thereof.
In the above illustration, x may have any value larger than zero
but smaller or equal to 2. While z is usually 1 or 3, it can have
any value between 1 and 6. The precursor PAMAMOS/PPIOS dendrimer
may be of any number of generations having 3y or 4y number of
vinylsilyl or allylsilyl functional end groups per molecule where y
is 1, 2, 3, 4, or more, for example. Depending upon the particular
method used in preparing these precursor PAMAMOS/PPIOS dendrimers,
the precursor dendrimers may contain one or more layers of
organosilicon branch cells around their PAMAM or PPI interiors, and
the number of their layers and the composition of their branch
cells will necessarily determine the number and the particular type
of silicon atom containing moiety in the various arms of the
resulting multi-arm star polymer.
While the thiol can be any reactive aliphatic or aromatic R--SH
type of compound, the thiol is most preferably a compound R--SH
where R represents the group --(CH.sub.2).sub.c --CH.sub.3 in which
c is an integer in the range of 1-50. Thiols containing silicon
atoms can also be employed, if desired. The thiol addition reaction
is typically performed in solution, and can be monitored by a
variety of standard techniques among which are .sup.1 H, .sup.13 C,
or .sup.29 Si Nuclear Magnetic Resonance (NMR), mass or infrared
spectroscopy, dilute solution viscometry, Gel Permeation
Chromatography (GPC), and Size Exclusion Chromatography (SEC).
Representative of a typical condition for such a reaction is one in
which a mixture of methanol and tetrahydrofuran is used as the
solvent, and in which the reaction is carried out at a temperature
in the range of about 60-70.degree. C.
Representative of some thiols which can be used are ethanethiol
CH.sub.3 CH.sub.2 SH, 1-propanethiol CH.sub.3 CH.sub.2 CH.sub.2 SH,
1-butanethiol CH.sub.3 CH.sub.2 CH.sub.2 CH.sub.2 SH, isopentyl
mercaptan C.sub.5 H.sub.11 SH, heptanethiol C.sub.7 H.sub.15 SH,
1-dodecanethiol C.sub.12 H.sub.25 SH, and 1-octadecanethiol
C.sub.18 H.sub.37 SH.
Representative of some thiols containing a silicon atom which can
be used are (i) silanes such as mercaptotriphenylsilane and
(2-mercaptoethyl)trimethylsilane, and (ii) mercapto functional
silicones containing the group .ident.SiCH.sub.2 CH.sub.2 CH.sub.2
SH such as (mercaptopropyl)methylsiloxane polymers and
(mercaptopropyl)methylsiloxane dimethylsiloxane copolymers, or
mercapto functional silicones containing the group
.ident.SiCH.sub.2 CH(CH.sub.3).sub.2 SH such as
(mercaptoisobutyl)methylsiloxane polymers and
(mercaptoisobutyl)methylsiloxane dimethylsiloxane copolymers.
The epoxidation method used to prepare PAMAM/PPI based multi-arm
star polymers according to the invention involves the ring opening
addition of glycidoxy functionalized organosilicon compounds such
as monosubstituted epoxyalkylsilanes or monosubstituted
epoxyalkylpolysiloxanes to an amine or imine terminated PAMAM or
PPI dendrimer, as generally shown below in the case of a PAMAM
dendrimer and a monosubstituted epoxyalkylpolysiloxane:
##STR6##
In the above illustration, x may have any value larger than zero
but smaller or equal to 2. The value of z can vary generally from
3-6, and n has a value of one or more depending on the viscosity
and molecular weigh desired. Most preferred, are monoepoxypropoxy
functional polysiloxanes with viscosity and molecular weights
varying between 1-200 mm.sup.2 /s (centistoke) and 300-6,000,
respectively. The value of y can be from 3 to several thousand,
depending on the generation, i.e., 3(G +1) or 4(G +1) where G is
the generation being an integer ranging from 0 to 10.
While monoepoxypropoxy functional polysiloxanes such as the
siloxane compositions shown above are preferred, monosubstituted
epoxyalkylsilanes can also be used, and some representative silane
compositions are shown below. ##STR7##
The ring opening addition reaction is typically performed in a
polar solvent such as THF, methanol, isopropanol, or mixtures of
such polar solvents. If PAMAM dendrimers rather than PPI dendrimers
are used in this addition reaction, the reaction temperature should
not exceed about 80-90.degree. C. for periods of 12-24 hours, or
should not exceed 140.degree. C. for periods of about one hour.
Higher reaction temperatures can be employed, however, in the case
of PPI dendrimers.
It can be seen, therefore, that multi-arm star polymers of the
invention can comprise hydrophilic or hydrophobic type dendrimer
based cores with silicon containing arms, in which the composition
of the core can be PAMAM, PPI, PAMAMOS, PPIOS, and the number of
arms attached to the dendrimer based core is dependent upon the
functionality of the dendrimer based core used as precursor of the
multi-arm star polymer, as well as the degree of conversion
provided during its synthesis. As noted above, while the content of
silicon atoms per arm may preferably range from a single silicon
atom to about 30 silicon atoms, compositions containing up to 100
silicon atoms can be prepared, if desired.
It has been found that these multi-arm star polymers exhibit a
pronounced phase transfer ability, complexation potential, and an
ability to participate in forming inorganic-organic nanocomposites.
Thus, the hydrophobic character of the exterior arms of PAMAMOS and
PPIOS multi-arm star polymers renders them insoluble in water and
methanol, but at the same time, they are soluble in polar organic
solvents such as THF and chloroform, aliphatic hydrocarbons such as
n-hexane, and aromatic hydrocarbons such as toluene.
For example, this was demonstrated using a PAMAMOS multi-arm star
polymer prepared from 1-octadecanethiol C.sub.18 H.sub.37 SH, and a
PAMAMOS [3,1] DMVS, i.e., a PAMAMOS dendrimer prepared by adding
one layer of organosilicon (OS) branch-cells containing
dimethylvinylsilyl(DMVS) end groups to a generation 3 PAMAM
dendrimer. It provided a clear, slightly yellow solution when
dissolved in chloroform. Similarly, a closely related multi-arm
star polymer obtained from a generation 3 amine terminated PAMAM
and a monofunctional glycidoxy polysiloxane having a molecular
weight of about 1000, provided a clear, colorless solution when
dissolved in hexanes.
When an aqueous solution of CuSO.sub.4 is added to a vessel
containing either of these solutions, two immiscible layers are
formed. However, if the systems are thoroughly shaken, a distinct
color change was observed to rapidly occur. Thus, the yellow
chloroform solution turned green, while the aqueous layer either
completely or partially discolored, depending on the initial copper
salt concentration, the multi-arm star polymer concentration in the
organic phase, and the relative volume of the two phases.
These and similar examples demonstrate the ability of the multi-arm
silicon containing PAMAMOS and PPIOS star polymers to transfer
electrophiles such as inorganic cations such as Cu.sup.2+ from
their natural habitat in an aqueous medium to a hostile environment
such as an organic liquid.
While not being bound by the following theory, it is believed that
in the organic phase, and at or near the boundary with the aqueous
phase, PAMAMOS multi-arm star polymers have the ability to
rearrange their conformation in such a way as to orient the
hydrophilic dendrimer interior core towards the boundary and the
hydrophobic silicon containing arms towards the organic bulk phase.
In such a rearranged conformation, the strongly nucleophilic
tertiary amines of the dendrimer interior become capable of
attracting and complexing electrophiles such as inorganic cations
from the aqueous phase. This enables transport of such
electrophiles through the phase boundary and into the organic
layer, which is otherwise an environment in which such species do
not dissolve.
However, inside the hydrophilic, strongly complexing, dendritic
nanoenvironment, inorganic cations can be encapsulated and
protected from hostile organic surroundings by the hydrophobic
exterior arms of the multi-arm star polymer molecules, and since
the arms provide solubility for the entire host molecule, the arms
render the electrophiles soluble in the organic phase.
In addition, since an hydrophilic dendritic core is smaller than
the wavelength of visible light, i.e., its diameter typically
increases with each generation by less than about 1 nm per
generation, the size of any complex will remain too small to
interfere with visible light, and so this phenomenon results in a
clear, colored organic phases containing the dissolved inorganic
species. The color will depend upon the particular cation being
used, and it should be understood that cations other than Cu.sup.2+
can be employed, such as Cu.sup.1+, Fe.sup.2+, Fe.sup.3+,
Au.sup.3+, Ag.sup.+, Rh.sup.3+, Ni.sup.2+, and Cd.sup.2+, for
example.
It has also been determined that while being encapsulated inside
the dendritic interior of a PAMAMOS or PPIOS multi-arm star
polymer, such inorganic cations as well as other electrophiles, are
susceptible to chemical transformation. For example, when a
reducing agent such as hydrazine (H.sub.2 NNH.sub.2) was added to
the previously described two phase system containing the CuSO.sub.4
/H.sub.2 O and the CuSO.sub.4 /PAMAMOS multi-arm star
polymer/hexanes layers, the characteristic blue color of the
Cu.sup.2+ complex readily turned coppery in color, indicating a
reduction of the Cu.sup.2+ cations to elemental copper. The reduced
metal, however, remained soluble in the organic phase, within a
domain which did not interfere with visible light, allowing for
clarity of the coppery solution.
Such phenomenon render the silicon containing multi-arm star
polymers of this invention useful in a number of applications
including their use as phase transfer agents, molecular
encapsulators, surfactants, emulsifiers, personal care products,
catalysis, metal harvesting and metal regeneration, liquid
purification, environmental protection, compatibilization,
preparation of nanoscopic metal particles, metallurgy of alloys,
and in the preparation of unusual host/guest supramolecular
assemblies such as quantum dots.
EXAMPLES
The following examples are set forth in order to illustrate the
invention in more detail. In particular, Examples 1-4 are directed
to the preparation of the PAMAMOS dendrimers used in the Thiol
Addition Reactions in Examples 5-12; Examples 13-17 are
illustrative of the Epoxidation of PAMAM dendrimers; and Examples
18-21 illustrate some useful applications of these multi-arm star
polymers.
PAMAMOS DENDRIMERS
Example 1
Preparation of a PAMAMOS [3,1] DMVS dendrimer having
dimethylvinylsilyl (DMVS) end groups from a generation 3 EDA core
amine terminated PAMAM dendrimer and
chloromethyldimethylvinylsilane (CMDMVS)
A generation 3 EDA core PAMAM dendrimer having a nominal content of
32 NH.sub.2 end groups was lyophilized in methanol in a round
bottomed flask equipped with a Teflon.RTM. coated stirring bar, and
kept under partial vacuum overnight prior to its use. 3.66 g (0.53
mmol, 33.9 mmol of NH groups) of the obtained crisp white solid was
dissolved under nitrogen in 34.5 mL of N,N'-dimethylformamide
(DMF), and 6.1 mL (5.48 g, 40.45 mmol) of
chloromethyldimethylvinylsilane (CMDMVS) was added to the resulting
solution to achieve a molar ratio of the reacting functionalities
[ClCH.sub.2 ]/[NH] of 1:19. Following this procedure, NaHCO.sub.3
(4.03 g) was added to the mixture, a vertical condenser was
attached to the flask, and the reaction mixture was heated under
nitrogen to 80.degree. C., and stirred at that temperature for 121
hours. During this time, aliquots were periodically taken for
monitoring the progress of the reaction by .sup.1 H and .sup.13 C
NMR which was performed in deuterated methanol CD.sub.3 OD with
p-dioxane as a reference standard. Heating and stirring were then
stopped, and a sample was taken for NMR determination of the degree
of NH group conversion achieved during the process. The reaction
mixture was filtered, separated salts were rinsed with methanol,
and the joined liquids were dialyzed, first in a 50:50
methanol/water mixture, and then in pure methanol. Methanol was
evaporated, and the product in which no unreacted NH groups could
be detected, was dried overnight under partial vacuum. Analytical
data for this product follows. .sup.1 H NMR in CD.sub.3 OD: 0.14
ppm (s, Si--CH.sub.3); 2.11-3.34 ppm (PAMAM dendrimer protons);
5.71-6.26 ppm (Si--CH.dbd.CH.sub.2). .sup.13 C NMR in CD.sub.3 OD:
-2.80 ppm (Si--CH.sub.3); 34.77 ppm (--CH.sub.2 --C(O)--NH--);
38.25 ppm (--CO--NH--CH.sub.2 --CH.sub.2 --N--(CH.sub.2
--Si(CH.sub.3).sub.2 CH.dbd.CH.sub.2).sub.2); 38.58 ppm
(--CO--NH--CH.sub.2 --CH.sub.2 --N.dbd.); 50.50 ppm
(--CO--NH--CH.sub.2 --CH.sub.2 --N--(CH.sub.2 --Si(CH.sub.3).sub.2
CH.dbd.CH.sub.2).sub.2); 51.09 ppm (--CO--NH--CH.sub.2 --CH.sub.2
--N.dbd. and N--CH.sub.2 --CH.sub.2 --CONH--(CH.sub.2).sub.2
--Si.ident.); 53.48 ppm (.dbd.N--CH.sub.2 --CH.sub.2
--CONH--(CH.sub.2).sub.2 --N.dbd.); 61.14 (.dbd.N--CH.sub.2
--Si.ident.); 113.16 and 139.67 ppm (.ident.Si--CH.dbd.CH.sub.2);
174.16 and 174.45 ppm (--CO--NH--). .sup.29 Si NMR in CD.sub.3 OD:
-8.74 ppm (.dbd.N--CH.sub.2 --Si(CH.sub.3).sub.2 CH.dbd.CH.sub.2).
Differential Scanning Calorimetry (DSC) (under nitrogen from
-50.degree. C. to 100.degree. C. at a heating rate of 10.degree.
C./min): Glass Temperature T.sub.g =-2.5.degree. C.
Example 2
Preparation of PAMAMOS [3,1] DMVS dendrimer having
dimethylvinylsilyl (DMVS) end groups from a generation 3 EDA core
amine terminated PAMAM dendrimer and in situ prepared
iodomethyldimethylvinylsilane (IMDMVS)
Chloromethyldimethylvinylsilane (CMDMVS) (8.1 mL, 7.22 g, 53.64
mmol), 18-Crown-6 ether represented by the structure ##STR8##
(0.72 g, 2.68 mmol, 5%/[Cl.sup.- ]), sodium iodide (8.87 g, 59
mmol) and DMF (20 mL) were mixed under nitrogen in a dry 250 mL two
neck, round bottom flask equipped with a nitrogen inlet and an
outlet, a condenser, and mechanical stirrer. Stirring was
initiated, the mixture was heated to 60.degree. C., and kept at
that temperature overnight to allow for formation of
iodomethyldimethylvinylsilane (IMDMVS). To the mixture was added a
solution of a generation 3 EDA core PAMAM dendrimer (4.82 g, 0.7
mmol, 44.7 mmol of NH groups) lyophilized as described in Example
1, and NaHCO.sub.3 (6.77 g, 80.46 mmol) in DMF (30 mL). The mixture
was vigorously stirred under nitrogen and heated to 80.degree. C.
Periodically, a sample of the reaction mixture was taken for NMR
monitoring. When a complete disappearance of the silane reagent was
detected after 50 hours of reaction, stirring was stopped, and the
reaction mixture was allowed to cool to room temperature. The
solids were filtered, and the PAMAMOS dendrimer product was
isolated from the liquid phase by two stage dialysis. The dialysis
was performed, first in a 50:50 methanol/water mixture, and then in
pure methanol, using a dialysis bag composed of Spectra/Por 7
dialysis membranes, having a molecular weight cut off (MWCO) of
3500 from Spectrum Medical Industries, Houston, Tex. Spectral
features and physical properties of the product were determined to
be the same as spectral features and physical properties shown
above in Example 1.
The preparation of other dendrimers, similar to the dendrimers
prepared in Examples 1 and 2 from generation 3 dendrimers, is
described in Examples 3 and 4, in which generation 4 and generation
1 dendrimers, respectively, are employed.
Example 3
Preparation of a PAMAMOS [4,1] DMVS dendrimer having
dimethylvinylsilyl (DMVS) end groups from a generation 4 EDA core
amine terminated PAMAM dendrimer and
chloromethyldimethylvinylsilane (CMDMVS)
A generation 4 EDA core PAMAM dendrimer (5.1 g, 0.36 mmol, 45.95
mmol of NH groups) in methanol, having a nominal content of 64
NH.sub.2 end groups, was dried and then lyophilized from water
overnight to form a crisp white solid. This procedure was analogous
to the procedure used in Example 1, except that the dendrimer was
dissolved in 1-methyl-2-pyrrolidinone (NMP). The components of the
reaction mixture were 7.42 g of chloromethyldimethylvinylsilane
(CMDMVS) (54.77 mmol), NMP (45 mL), and NaHCO.sub.3 (5.69 g). The
reaction mixture was heated to 80.degree. C. with stirring for one
week. After reaction was complete as confirmed by .sup.1 H and
.sup.13 C NMR, the reaction mixture was filtered, salts were washed
with methanol, the liquids were combined, and dialyzed, first in a
1:1 methanol/water mixture for two days, and then in pure methanol
for one 1 week, using a dialysis bag composed of Spectra/Por 7
dialysis membranes having a MWCO of 1000. Methanol was evaporated
and the product was dried overnight under vacuum yielding 7.33 g
(75.9%). Spectral features were similar to those features obtained
for the PAMAMOS [3,1] DMVS dendrimer in Example 1, and the features
indicated complete reaction conversion. DSC (under nitrogen from
-80 to 100.degree. C. at 10.degree. C./min): T.sub.g =-6.1.degree.
C.
Example 4
Preparation of PAMAMOS [1,1] DMVS dendrimer having
dimethylvinylsilyl (DMVS) end groups from a generation 1 EDA core
amine terminated PAMAM dendrimer and
chloromethyldimethylvinylsilane (CMDMVS)
The procedure used in this example was similar to the procedure in
Example 3, except that 9.4 g of a lyophilized generation 1 EDA core
PAMAM dendrimer (7.13 mmol, 114.08 mmol NH groups) was employed.
The components of the reaction mixture were 18.8 g of CMDMVS
(136.90 mmol), NMP (60 mL), and NaHCO.sub.3 (9.40 g). The reaction
mixture was heated at 80.degree. C. for one week. After the
reaction was completed as evidenced by NMR, salts were filtered and
washed with methanol. The liquids were combined and dialyzed as in
Example 3. Drying in a partial vacuum resulted in a yield of 16.47
g of the product (76.9%). Its spectral features were similar to the
features in Example 3. DSC (under nitrogen from -80 to 100.degree.
C. at 10.degree. C./min) T.sub.g =-6.0.degree. C.
THIOL ADDITION REACTIONS
Example 5
Preparation of a 64 arm star polymer having polymethylene
[--CH.sub.2 --Si--(CH.sub.2).sub.2 --S--(CH.sub.2).sub.11
--CH.sub.3 ] arms emanating from a generation 3 EDA core amine
terminated PAMAM dendrimer
A three neck round bottom flask was equipped with a vertical
condenser, a nitrogen inlet and an outlet, a rubber septum, and a
Teflon.RTM. coated stirring bar. Either of the PAMAMOS [3,1] DMVS
dendrimers of Example 1 or Example 2 (0.86 g, 0.0673 mmol, 4.29
mmol of vinyl groups) were separately treated in this example, and
lyophilized overnight prior to their use as in Example 1, and
dissolved under nitrogen in anhydrous tetrahydrofuran THF (4.0 mL).
2,2'-azobisisobutyronitrile AIBN (0.043 g, 0.26 mmol, 6.6%/[SH])
was dried under a partial vacuum, mixed under nitrogen with
1-dodecanethiol (0.96 mL, 0.81 g, 4 mmol), and the mixture was
added under nitrogen into the stirred dendrimer solution in the
reaction flask. The mixture was heated to 65.degree. C. and
maintained at that temperature for 45 hours. Periodically, samples
were taken for monitoring of the reaction progress by NMR which was
determined by tracking disappearance of signals characteristic of
dendrimer vinyl groups. The reaction was stopped when no more of
the groups could be detected, and the mixture was extracted under
dialysis conditions twice, first with acetone, and then in
methanol. The resulting 100% alkyl-substituted multi-arm star
polymer product in each case was insoluble in acetone and methanol,
but soluble in toluene, n-hexane, and chloroform. .sup.1 H NMR in
deuterated chloroform CDCl.sub.3 : 0.1 ppm (s, .ident.Si--CH.sub.3
and --CH.sub.2 --Si.ident.); 0.85 ppm (s, --CH.sub.2 --CH.sub.3);
1.22 ppm (s, --(CH.sub.2).sub.11 -alkyl chain); 1.95-3.35 ppm
(PAMAM dendrimer protons and --S--CH.sub.2 --). .sup.13 C NMR in
CDCl.sub.3 : -3.50 ppm (.ident.Si--CH.sub.3); 0.15 ppm
(.ident.Si--CH.sub.2 --); 14.06 ppm (--CH.sub.2 --CH.sub.3);
28.99-29.58 ppm (m, --CH.sub.2).sub.11 -alkyl chain); 31.84 ppm
(--S--CH.sub.2 --CH.sub.2 --); 32.02 (--S--CH.sub.2 --);
33-98-37.55 and 49.02-52.38 ppm (PAMAM dendrimer); 59.57 ppm (PAMAM
dendrimer); 130-140 ppm (empty base line in the vinyl group
region); 172.5 and 173 ppm (--CO--NH--). .sup.29 Si NMR in
CDCl.sub.3 : -10 to -5 ppm (empty base line in the Si-vinyl group
region); 0.39 ppm (.dbd.N--CH.sub.2 --Si(CH.sub.3).sub.2
(--CH.sub.2 --CH.sub.2 --S--R). DSC (under nitrogen from
-100.degree. C. to 150.degree. C. at 10.degree. C./min): T.sub.m
=-26.degree. C. Differential Thermogravimetric Analysis in N.sub.2
at 20.degree. C./min: a single step weight loss process onset at
160.degree. C., maximum rate at 370.degree. C., end at 490.degree.
C., leaving total weight residue of 14.4 percent.
Example 6
Preparation of a 64 arm star polymer having polymethylene
[--CH.sub.2 --Si--(CH.sub.2).sub.2 --S--(CH.sub.2).sub.17
--CH.sub.3 ] arms emanating from a generation 3 tetradendron PAMAM
dendrimer core
The multi-arm star polymer in this example was prepared by a
procedure similar to Example 5, except that 1-octadecanethiol was
used instead of 1-dodecanethiol, and THF was used instead of
acetone and methanol in the dialysis for the product purification.
The components of the reaction mixture were PAMAMOS [3,1] DMVS
(0.43 g, 0.0338 mmol, 2.01 mmol of vinyl groups); THF (2.0 mL);
1-octadecanethiol (0.81 mL, 0.73 g, 2.54 mmol); and AIBN (30.5 mg,
0.013 mmol, 5%/[SH]). The total reaction time at 65.degree. C. was
16.25 hours. NMR spectra of the product corresponded with spectra
in Example 5. Gel Permeation Chromatography GPC in a THF/MeOH
mixture (98:2) at 1 mL/min with PL gel columns: a single sharp peak
at 18 min with a slight shoulder at longer retention times;
polydispersity less than 1.2. DSC (in nitrogen from -20.degree. C.
to 100.degree. C. at 10.degree. C./min), two endotherms at
40.degree. C. (strong), and at 53.degree. C. (medium to weak),
reproducible through three heating/cooling cycles, and for
1-octadecanethiol T.sub.m =31-35.degree. C.
Example 7
Preparation of an 128 arm star polymer having [--CH.sub.2
--Si--(CH.sub.2).sub.2 --S--(CH.sub.2).sub.2 --CH.sub.3 ] arms
emanating from a generation 4 tetradendron PAMAM dendrimer core
The procedure used in this example was similar to Example 5, except
the solvent was a 1:4 mixture of THF/MeOH. The 128 arm star polymer
was formed from 2.23 g PAMAMOS [4,1] DMVS (0.08 mmol, 10.24 mmol of
vinyl groups) dissolved in a THF (40.4 mL)/MeOH (10.7 mL) mixture.
To the mixture was added 0.13 g AIBN (0.79 mmol, 5.0%/[SH]) in THF
(1.4 g), and 1.21 g of 1-propanethiol (15.89 mmol). The mixture was
heated to 65.degree. C. overnight. NMR indicated completion of the
reaction, and the product was dialyzed in a 1:2 MeOH/hexane mixture
for one week. The product was dried in a partial vacuum yielding
2.30 g (75.7%). The spectral features of the product were similar
to the features of the product in Example 5. DSC under nitrogen
from -80 to 100.degree. C. at 10.degree. C.C/min: T.sub.g
=-4.7.degree. C.
Example 8
Preparation of an 128 arm star polymer having [--CH.sub.2
--Si--(CH.sub.2).sub.2 --S--(CH.sub.2).sub.6 --CH.sub.3 ] arms
emanating from a generation 4 tetradendron PAMAM dendrimer core
Following the procedure used in Example 7, the 128 arm star polymer
was formed by adding heptanethiol (2.10 g, 15.88 mmol) to a
reaction mixture of 2.3 g PAMAMOS [4,1] DMVS (0.08 mmol, 10.24 mmol
of vinyl groups), 0.13 g AIBN (0.79 mmol, 5.0%/[SH]), THF (42.3
mL), and MeOH (8.5 g). The mixture was heated to 65.degree. C.
overnight, and the sample was purified by dialysis as in Example 7,
yielding 2.62 g of product (72.1%). The spectral features were
similar to features in Example 5. DSC under nitrogen from -80 to
100.degree. C. at 10.degree. C./min) T.sub.g =-16.0.degree. C.
Example 9
Preparation of an 128 arm star polymer having [--CH.sub.2
--Si--(CH.sub.2).sub.2 --S--(CH.sub.2).sub.17 --CH.sub.3 ] arms
emanating from a generation 4 tetradendron PAMAM dendrimer core
An 128 arm star polymer was formed by a procedure similar to
Example 7 using as reaction components 2.3 g PAMAMOS [4,1] DMVS
(0.08 mmol, 10.24 mmol of vinyl groups), 0.13 g AIBN (0.79 mmol,
5.0%/[SH]), 4.56 g of octadecanethiol (15.91 mmol), THF (42.0 mL),
and MeOH (10.7 mL). The mixture was heated to 65.degree. C.
overnight and purified by dialysis as in Example 7 yielding 3.66 g
of product (73.2%). The spectral features were similar to features
described in Example 5. Physical features of the viscous material
were similar to analyses in Example 6. DSC under nitrogen from -80
to 100.degree. C. at 10.degree. C./min): two endotherms at
41.6.degree. C. and 55.0.degree. C., T.sub.m for
1-octadecanethiol=31.degree. C.
Example 10
Preparation of a 16 arm star polymer having [--CH.sub.2
--Si--(CH.sub.2).sub.2 --S--(CH.sub.2).sub.2 --CH.sub.3 ] arms
emanating from a generation 1 tetradendron PAMAM dendrimer core
A 16 arm star polymer was formed by a procedure similar to Example
7 using as the reaction components 4.8 g PAMAMOS [1,1] DMVS (1.61
mmol, 19.3 mmol of vinyl groups), 0.16 g AIBN (0.97 mmol,
5.0%/[SH]), 1.47 g of propanethiol (19.3 mmol), THF (44.3 mL), and
MeOH (12.4 mL). The mixture was heated to 65.degree. C. overnight
and purified by dialysis as in Example 7. The spectral features
were similar to the features in Example 5. DSC under nitrogen from
-80 to 100.degree. C. at 10.degree. C./min): T.sub.g1
=-32.6.degree. C. and T.sub.g2 =5.2.degree. C.
Example 11
Preparation of 16 arm star polymer having [--CH.sub.2
--Si--(CH.sub.2).sub.2 --S--(CH.sub.2).sub.11 --CH.sub.3 ] arms
emanating from a generation 1 tetradendron PAMAM dendrimer core
A 16 arm star polymer was formed by a procedure comparable to
Example 7 using as reaction components 4.8 g PAMAMOS [1,1] DMVS
(1.61 mmol, 19.3 mmol of vinyl groups), 0.16 g AIBN (0.97 mmol,
5.0%/[SH]), 3.91 g of dodecanethiol (19.3 mmol), THF (44.3 mL), and
MeOH (12.4 mL). The mixture was heated to 65.degree. C. overnight
and purified by dialysis as described in Example 7. Spectral
features were similar to features described in Example 5. DSC under
nitrogen from -80 to 100.degree. C. at 10.degree. C./min): T.sub.m
=-4.3.degree. C.
Example 12
Preparation of 16 arm star polymer having [--CH.sub.2
--Si--(CH.sub.2).sub.2 --S--(CH.sub.2).sub.17 --CH.sub.3 ] arms
emanating from a generation 1 tetradendron PAMAM dendrimer core
A 16 arm star was formed by a procedure similar to Example 7 using
as the reaction components 4.8 g PAMAMOS [1,1] DMVS (1.61 mmol,
19.3 mmol of vinyl groups), 0.16 g AIBN (0.97 mmol, 5.0%/[SH]),
5.54 g of octadecanethiol (19.3 mmol), THF (44.3 mL), and MeOH
(12.4 mL). The mixture was heated to 65.degree. C. overnight and
purified by dialysis as in Example 7 to yield 3.66 g of product
(73.2%). The spectral features were similar to features in Example
5. DSC under nitrogen from -100 to 100.degree. C. at 10.degree.
C./min): two endotherms at 41.2.degree. C. and 56.1.degree. C.
EPOXIDATIONS OF PAMAM DENDRIMERS
Example 13
Preparation of a 32 arm star polymer having {--CH.sub.2
--CH(OH)--CH.sub.2 --O--(CH.sub.2).sub.3 --[Si(CH.sub.3).sub.2
O].sub.n --Si(CH.sub.3).sub.2 --C.sub.4 H.sub.9 } arms (n.sub.av.
=10-11; MW.about.1000) emanating from a generation 2 tetradendron
PAMAM dendrimer
A 500 mL three neck round bottom flask was equipped with a vertical
condenser, a nitrogen inlet and an outlet, and a Teflon.RTM. coated
stirring bar. The flask was charged with a 2-propanol solution (80
mL) of a generation 2 EDA core amine terminated PAMAM dendrimer
(2.31 g of a 26.46 weight percent methanol solution, 6.00 mmol of
NH groups) and a mono-(2,3,-epoxypropyl)propylether polysiloxane)
(EpPS) (M.sub.n =1000) (7.20 g, 7.20 mmol, [epoxy]/[NH]=1.2). The
reaction mixture was stirred for 24 hours under nitrogen in a
65.degree. C. oil bath. Volatiles were stripped under a reduced
pressure using a rotoevaporator, and the oil remaining was
thoroughly washed with methanol using six 50 mL portions to remove
unreacted reagents. A colorless viscous product was obtained (2.92
g, 81% yield of --NHR product). .sup.1 H NMR in CDCL.sub.3 : 0.01
ppm (s with satellites, .ident.Si--CH.sub.3); 0.42-0.50 ppm (m,
--SiMe.sub.2 CH.sub.2 --); 0.82 ppm (t, --CH.sub.2 CH.sub.3);
1.23-1.27 ppm [m, (--CH.sub.2).sub.2 CH.sub.3 ]; 1.53 ppm (b,
--OCH.sub.2 CH.sub.2 --); 2.29-3.80 ppm (bm, PAMAM dendrimer
protons and --NHCH.sub.2 CH(OH)CH.sub.2 OCH.sub.2 --); 7.80 ppm (b,
NH and OH). .sup.13 C NMR in CDCl.sub.3 : 0.92 ppm (s with
satellites, .ident.SiCH.sub.3); 13.67 ppm (s, --CH.sub.2 CH.sub.3);
14.06 ppm (s, --SiMe.sub.2 [CH.sub.2 ].sub.3 CH.sub.3 or
--SiMe.sub.2 [CH.sub.2 ].sub.2 CH.sub.2 --O--); 17.87 ppm (s,
--SiMe.sub.2 [CH.sub.2 ].sub.3 CH.sub.3 or SiMe.sub.2 [CH.sub.2
].sub.2 CH.sub.2 --O--); 23.01 ppm (s, --SiMe.sub.2 [CH.sub.2
].sub.3 CH.sub.3 or --SiMe.sub.2 [CH.sub.2 ].sub.2 CH.sub.2 --O--);
25.37 ppm (s, --SiMe.sub.2 [CH.sub.2 ].sub.3 CH.sub.3 or
--SiMe.sub.2 [CH.sub.2 ].sub.2 CH.sub.2 --O--); 26.26 ppm (s,
--SiMe.sub.2 [CH.sub.2 ].sub.3 CH.sub.3 or --SiMe.sub.2 [CH.sub.2
].sub.2 CH.sub.2 --O--); 34.16 ppm (bs, CH.sub.2 CONH--); 37.71 ppm
(s, PAMAM CH.sub.2 --); 39. 25 ppm (s, PAMAM CH.sub.2 --); 41.47
ppm (s, NH.sub.2 [CH.sub.2 ].sub.2 --); 42.21 ppm (s, NH.sub.2
[CH.sub.2 ].sub.2 --); 48.85 ppm (s, PAMAM CH.sub.2 --); 50.32 (s,
PAMAM CH.sub.2 --); 52.46 ppm (s, PAMAM-CH.sub.2 --); 59.00 ppm (s,
--NCH.sub.2 CHOH); 60.50 ppm (s, NCH.sub.2 CHOH); 67.38 ppm (s,
disubstituted .dbd.CHOH), 68.91 ppm (s, monosubstituted .dbd.CHOH);
73.29 ppm (s, .dbd.CHOHCH.sub.2 --); 73.62 ppm (s,
.dbd.CHOHCH.sub.2 --); 74.34 ppm (s, --OCH.sub.2 CH.sub.2 --);
172.86 ppm (s, C.dbd.O); the ratio of integrals for --CH.sub.2
--CH.sub.2 --CONH-- at 34.16 ppm normally 28 atoms per dendrimer,
and --CH.sub.2 --CHOH-- at 68.91 ppm, indicated a degree of --NHR
substitution of 84 percent. .sup.1 H NMR showed no presence of
unreacted epoxy ring protons indicating a pure product. On average,
the PAMAMOS multi-arm star polymer was considered as having
--CH.sub.2 --CH(OH)--CH.sub.2 --O--(CH.sub.2).sub.3
--[Si(CH.sub.3).sub.2 O].sub.x --Si(CH.sub.3).sub.2 --C.sub.4
H.sub.9 arms emanating from secondary amine --NH-- bridging groups,
although both .sup.13 C and .sup.1 H NMR showed trace amounts of
unreacted --CH.sub.2 CH.sub.2 NH.sub.2 groups and disubstituted
tertiary amine --N<units. IR on KBr, only some peaks listed:
3292 cm.sup.-1 v(N--H or O--H); 3074 cm.sup.-1 v(N--H or O--H);
1648 cm.sup.-1 v(C.dbd.O); 1555 cm.sup.-1 v(CNH); 1092 cm.sup.-1
v(Si--O--Si); 1024 cm.sup.-1 v(Si--O--Si).
Example 14
Preparation of a 64 arm star polymer having {--CH.sub.2
--CH(OH)--CH.sub.2 --O--(CH.sub.2).sub.3 --[Si(CH.sub.3).sub.2
--O].sub.n --Si(CH.sub.3).sub.2 --C.sub.4 H.sub.9 } arms (n.sub.av.
=10-11; MW.about.1000) emanating from a generation 3 tetradendron
PAMAM dendrimer
A 50 mL two neck round bottom flask was equipped with a vertical
condenser, a nitrogen inlet and an outlet, a rubber septum, and a
Teflon.RTM. coated stirring bar. The flask was charged with a
methanol solution of a generation 3 amine terminated EDA core PAMAM
dendrimer (0.71 g of a 31.02 weight percent solution, dendrimer:
0.22 g, 0.032 mmol, 2.03 mmol of NH groups); methanol (1.4 mL,
total methanol present including solvent from the PAMAM dendrimer
solution: 2.0 mL); a mono-(2,3-epoxypropyl)propylether terminated
polysiloxane (EpPS) (M.sub.n =1000) (2.02 g, 2.02 mmol,
[epoxy]/[NH]=0.996), and THF (2.0 mL). The reaction mixture was
stirred and heated to 70.degree. C. Stirring was stopped after 17
hours, the mixture was poured into a 10 times larger volume of
methanol, and allowed to settle under refrigeration. Two phases
formed after 17 days, one a heavier oily phase at the bottom, and
the other a lighter cloudy methanol phase at the top. The methanol
phase was decanted, the oil was redissolved in methylene chloride,
and the solvent was evaporated under a partial vacuum. .sup.1 H NMR
in CDCl.sub.3 : 0.05 ppm (.ident.Si--CH.sub.3); 0.5 ppm (--CH.sub.2
--Si(CH.sub.3).sub.2 --O--); 0.85 ppm (--CH.sub.2 --CH.sub.3);
2.1-3.95 ppm (PAMAM dendrimer protons); 7.95 ppm (--CO--NH--).
.sup.29 Si NMR in CDCl.sub.3 : 3 peaks at -17.3, -16.88, and 6.03
ppm. .sup.13 C NMR in CDCl.sub.3 : from the ratio of integrals for
--CH.sub.2 --CH.sub.2 --CO--NH-- at 34.3 ppm which is nominally 60
atoms per dendrimer and for Si--CH.sub.3 at 0 ppm which is
nominally 22 atoms per arm, assuming x.sub.av. was 11, the number
of arms attached per dendrimer was 58, and the degree of NH
substitution was 91 percent.
Example 15
Preparation of the 64 arm star polymer of Example 14 in a single
solvent
The multi-arm star polymer of Example 14 was prepared by reacting a
generation 3 EDA core amine terminated PAMAM dendrimer (1 g of a
27.5 weight percent methanol solution, 2.55 mmol of NH groups), and
a mono-(2,3-epoxypropyl)propylether polysiloxane (EpPS) (M.sub.n
=1000) (3.06 g, 3.06 mmol, [epoxy]/[NH]=1.2) in 2-propanol (80 mL),
under nitrogen at 70.degree. C. for 22 hours. Volatiles were
distilled under reduced pressure using a rotoevaporator, and the
remaining oil was washed with methanol three times using 30 mL
portions to remove unreacted reagents. The structure of the product
(2.28 g; 64% yield) was confirmed by NMR, and by IR on KBr in
cm.sup.- : 800 (s.s., Si--CH.sub.3); 1025-1092 (s.d., Si--O--Si);
1261 (s.s., Si--CH.sub.3); 1413 and 1447 (w.s., Si--CH.sub.3); 1551
(m.s., NH); 1646 (m.s., C.dbd.O); 2861 and 2928 (m.s., CH.sub.2);
2874 (m.s., CH.sub.3); 2962 (s.s., CH.sub.3); 3080 (w.s., NH) and
3300 (m.s., NH); where s.s. is strong singlet, s.d. is strong
doublet, w.s. is weak singlet, and m.s. is medium singlet. Size
Exclusion Chromatography/Multiple Angle Laser Light Scattering
SEC-MALLS (toluene; PL gel B columns; MW values relative to PS):
M.sub.n =64800; M.sub.w =66700, PD=1.03, indicated a 93 percent NH
substitution.
Example 16
Preparation of an 128 arm star polymer having {--CH.sub.2
--CH(OH)--CH.sub.2 --O--(CH.sub.2).sub.3 --[Si(CH.sub.3).sub.2
O].sub.n --Si(CH.sub.3).sub.2 --C.sub.4 H.sub.9 arms (n.sub.av.
=10-11; MW.about.1000) emanating from a generation 4 tetradendron
PAMAM dendrimer
The multi-arm star polymer in this example was prepared by a
procedure analogous to Example 13. The reaction mixture components
were a 2-propanol solution (80 mL) of a generation 4 EDA core amine
terminated PAMAM dendrimer (2.89 g of a 23.07 weight percent
methanol solution, 6.00 mmol of NH groups), and a
mono-(2,3,-epoxypropyl)propylether polysiloxane (EpPS) (M.sub.n
=1000) (7.20 g, 7.20 mmol, [epoxy]/[NH]=1.2). The colorless viscous
product (2.98 g, yield 81% of --NHR product) showed .sup.1 H and
.sup.13 C NMR in CDCl.sub.3 and IR on KBr completely corresponding
to the spectra in Example 13. The ratio of integrals for --CH.sub.2
--CH.sub.2 --CONH-- at 34.07 ppm normally 124 atoms per dendrimer,
and --CH.sub.2 --CHOH-- at 68.89 ppm, indicated that the average
degree of --NH.sub.2 substitution to the --NH-arms was 72
percent.
Example 17
Preparation of a 4 arm star polymer having {--CH.sub.2
--CH(OH)--CH.sub.2 --O--(CH.sub.2).sub.3 --[Si(CH.sub.3).sub.2
O].sub.n --Si(CH.sub.3).sub.2 --C.sub.4 H.sub.9 arms (n.sub.av.
=64-65; MW.about.5000) from a generation 0 tetradendron PAMAM
dendrimer
The multi-arm star polymer in this example was also prepared by a
procedure analogous to Example 13. The reaction mixture components
were a 2-propanol solution (80 mL) of a generation 0 EDA core amine
terminated PAMAM dendrimer (0.38 g of a 45.59 weight percent
methanol solution, 2.70 mmol of NH groups), and a
mono-(2,3,-epoxypropyl)propylether polysiloxane (EpPS) (M.sub.n
=5000) (15.00 g, 3.00 mmol, [epoxy]/[NH]=1.11). A viscous oil
residue was obtained and after stripping volatiles under a reduced
pressure in a rotoevaporator, it was extracted with three portions
of 50 mL hexanes, followed by filtration. Hexanes were evaporated
under a reduced pressure in the rotoevaporator, and the product was
dried in a partial vacuum for 16 hours. A colorless viscous oil was
obtained (14.8 g) showing the following IR on KBr, with only some
peaks listed: 3299 cm.sup.-1 v(N--H or O--H); 3047 cm.sup.-1 v(N--H
or O--H); 1647 cm.sup.-1 v(C.dbd.O); 1558 cm.sup.-1 v(CNH); 1096
cm.sup.-1 v(Si--O--Si); 1022 cm.sup.-1 v(Si--O--Si). No PAMAM
signals were observed in either the .sup.1 H or .sup.13 C NMR
spectra. While not being bound, the reason postulated is that the
high content of dimethylsiloxy units in long arms of this
particular star polymer suppressed the small PAMAM interior.
However, the hexanes soluble crude product showed the presence of
PAMAM segments, which in their unreacted form, are not soluble in
hexane.
APPLICATIONS OF MULTI-ARM STAR POLYMERS
Example 18
Preparation of Green Chloroform by phase transfer and
solubilization of Cu.sup.2+ cations from an aqueous solution
The 64 arm star polymer of Example 6 was dissolved in chloroform
and provided a clear yellow colored solution. A blue colored water
solution of CuSO.sub.4 was added, and a non-mixable two-phase
system was produced consisting of a blue aqueous top layer and a
yellow organic bottom layer. The system was vigorously stirred for
about 60 minutes and remained two-phased, but the organic
chloroform bottom layer became colored green. This change in
coloration from yellow to green remained for several weeks and no
precipitate formation was observed.
Example 19
Preparation of Blue Methylene Chloride and Blue Chloroform by phase
transfer and solubilization of Cu.sup.2+ cations from an aqueous
solution into an organic solvent
Multi-arm star polymers of Example 7, 8, and 9, were each dissolved
in methylene chloride and chloroform to provide six clear
solutions. A blue colored aqueous solution of CuSO.sub.4 was added
to each of these solutions and immiscible two-phase systems were
formed consisting of a blue aqueous layer on top of a colorless
organic layer. The six systems were each vigorously shaken for one
hour to form emulsions. The emulsions were left to settle, and they
separated into two immiscible phases. In each case, the organic
phase was colored deep blue indicating the presence of Cu.sup.2+
cations.
Example 20
Preparation of Blue Hexanes by phase transfer and solubilization of
Cu.sup.2+ cations from an aqueous solution into hexane
The multi-arm star polymers of Example 7, 8, and 9 were each
dissolved in hexane to provide three clear solutions. A blue
colored aqueous solution of CuSO.sub.4 was added to each of the
three clear solutions to form immiscible two-phase systems each
consisting of a colorless hexane layer on top of a blue aqueous
layer. The three systems were each vigorously shaken for 1 hour to
form emulsions. The emulsions were left to settle and separated
into two immiscible phases. In each case, the organic phase was
colored deep blue indicating the presence of Cu.sup.2+ cations.
Example 21
Preparation of Blue Hexanes by phase transfer, solubilization of
Cu.sup.2+ cations from an aqueous solution, and preparation of
hexanes soluble Cu.sup.0 nano-composites
The 32 arm star polymer of Example 13 (0.045 g) was dissolved in
hexanes (2 mL) to provide a clear colorless solution. A
bluish-green opaque solution of Cu(OC(O)CH.sub.3).sub.2 (0.0443 g,
2.22.times.10.sup.-5 mol) in water (1 mL) and methanol (0.5 mL)
mixture was added to the solution and the two-phase system was
vigorously shaken for about 30 minutes. When the two phases
reformed after standing, the lighter organic hexanes phase turned
clear blue, while the heavier aqueous phase faded but remained
bluish-green and opaque. Hydrazine (0.1 g, 3.13 mmol) was added to
the system, and the system was again shaken for about one minute.
Both phases gradually turned a red-brown indicating a reduction of
Cu.sup.2+ into Cu.sup.0. After a short period of time, the Cu.sup.0
in the aqueous phase deposited to the glass walls of the container
to form a copper mirror. The aqueous phase turned clear and
colorless but the hexane phase remained stable red-brown,
indicating that elemental copper remained soluble in an hostile
environment. The copper remained encapsulated within the PAMAM
interior of the 16 arm star polymer.
Other variations may be made in compounds, compositions, methods,
cations, salts, and metals described herein without departing from
the essential features of the invention. The embodiments of the
invention specifically illustrated herein are exemplary only and
not intended as limitations on their scope except as defined in the
appended claims.
* * * * *